Copying machine and method

ABSTRACT

Efficient utilization of photosensitive intermediate and production of copies at a high rate of speed are accomplished in an automatic copying machine employing a delayed development copying method.

United States Patent inventor Appl. No.

Filed Assignee Burt K. Sagawa Minneapolis, Minn. 814,545

- Apr. 9, 1969 Patented Dec. 14, 1971 Minnesota Mining and Manuiacturing Company St. Paul, Minn.

COPYING MACHINE AND METHOD 10 Claims, 3 Drawing Figs.

U.S.Cl 219/216, 250/65 T, 355/107 int. Cl (i03g 15/06 [50] Field oISearch 219/216, 388; 250/65.1, 65.2; 355/107 [56] References Cited UNITED STATES PATENTS 3,211,074 10/1965 Heiart et a1. 355/107 3,318,219 5/1967 Anderson 355/100 Primary Examiner-C. L. Alhritton Attorney-Kinney, Alexander Sell, Steldt & Delahunt ABSTRACT: Efficient utilization of photosensitive intermediate and production of copies ,at a high rate of speed are accomplished in an automatic copying machine employing a delayed development copying method.

PATENIED [1m 4m COPYING MACHINE AND METHOD This invention relates to the copying of graphic originals by a process involving both light and heat. The copying process employed, and sheet materials useful therein, are in many particulars analogous to those described in Workman US. Pat. No. 3,094,417. One form of copying apparatus using the process and sheet materials of that patent has been described in Anderson U.S. Pat. No. 3,3 l8,2l9.

As described in the prior art, a light-desensitizable intermediate is first placed against the original in reflex position and the two are exposed to light. The intermediate is then placed against a copysheet and the composite is heated. The residual light-sensitive reactant remaining at the image areas of the intermediate is thereby transferred to and reacted with a coreactant in the copysheet, to produce on the copysheet a visible reproduction of the original. image.

The present invention likewise provides for reflex exposure of original and intermediate, and subsequent heating of intermediate and copysheet, with formation of a visible copy, but at greatly increased copying speeds and with increased efficiency in the use of the sensitive intermediate. Where the prior art method and apparatus were capable of producing not more than about five copies per minute, the novel version herein to be described is found to permit the production of at least about 15 copies per minute, using the same intermediate and copysheet. In copying both standard and legal size originals, the prior art might be unable to utilize as much as 20 percent of the intermediate; whereas the present invention is capable of upwards of 95-percent efficiency in the utilization of the intermediate.

These and other advantages are attained by means of the novel combination of components and methods of operation now to be described in terms of a specific and presently preferred illustrative embodiment, and in particular employing the novel principle of delayed development as therein incorporated. 3 t

In the drawing,

FIG. 1 is a view in perspective showing the apparatus in readiness for copying,

FIG. 2 is a schematic illustration in side elevation showing the relationship of the major components of the apparatus, and

FIG. 3 is a'partial end elevation showing the print roll and associated components of FIG. 2. i

The apparatus as shown in FIG. is enclosed within a cabinet having a control box 11 mounted thereon. The top 12 is in two sections. One section is provided with an opening 13 within which is located a feed chute 14; the other is hinged at the rear for access to the interior of the machine. The front 15 has an opening 16 within which a recovery chute 17 is provided. The two end panels 18, 19 are hingedly attached and provide further access to the interior of the cabinet. An opening 20 in panel 18 provides access to a delivery chute 21, the latter if desired being provided with a stop and serving as a collection area for copies delivered by the machine.

The panel of the control box 11 carries a main on-off switch 22, a ready light 23, indicators 24, a count switch 25, a density control switch 26, and a jog switch 27. Suitable electrical connection to a source of power is provided.

FIG. 2 illustrates the relationships between the feed chute 14, recovery chute 17, delivery chute 21 and other essential components of the apparatus. A supply drum 28 carries a supply of photosensitive intermediate 29 which is led around suitably positioned guide rollers to a print roller 30, past a light source 31 within a reflector 32, between a movable heating platen 33 and a belt 42, around a breaker bar or stripper bar 54 and past a drive unit 34 to a windup drum 35.

The feed chute area is provided with a feed roller 36 and drive rollers 37, 38. A stripper bar 39 and drive roller 41 are stationed behind the print roller 30, the stripper bar being positionable by means of an electromagnet 40. An additional guide plate 67 defines a continuation of the channel provided between the roller and the bar 39 when the latter is in the multiple-copy position.

The belt 42 travels around idler rollers 43 and 44, heating drum 45, drive roller 46, tracking roller 48, tensioning roller 47 and idler roller 49. A guide plate 68 parallels the belt 42 as it passes from idler roll 44 to heating drum 45, and a further guide plate 55 'follows the curve of drive roller 46. Copysheets from supply tray 50 are fed into the system by feed roller 51 and drive rollers 52, 53 and are directed by guide plates 68 and 55 around the drum 45 and into the chute 21 respectively.

Switches 59, 60, 64, 65 and 66, and contact elements 61, 63 control the operation of the apparatus in conjunction with the count switch 25 and with appropriate relays, delay mechanisms, pumps, valves and other auxiliary equipment in a manner to be disclosed. The several parts of the apparatus are conveniently driven from a single electric motor by means of positive action belt drives, but other equivalent mechanism may be substituted.

The print roller 30 is shown in FIG. 3 to have a perforate smooth-surfaced shell 57 and a hollow axle 58, the latter being connected to pump and valve means, not shown, for establishing positive or negative air pressures within the roller. FIG. 3 also shows the position of drive rollers 37 and 38, the latter being peripherally deeply scored to provide spaces for the feeler members of control switches 59, 60. Contact elements 61 and 63 make electrical contact with the drum 30 in the absence of an original. Guide plate 67, stripper bar 39, drive roller 41, and control roller 62, the latter being scored at the position of contact element 63, are also shown in FIG. 3. These and other components are supported on suitable frame members, not shown for reasons of clarity of illustration.

Since more copies are normally required of standard sized 83X ll inch originals than of other sizes, the print roller 30 is desirably dimensioned to hold such a shoe t st) that a number of copies may be made as the same original remains wrapped about the roller. Single copies of standard-sized sheets may also be made, the original then being removed after a single pass. For copying longer of shorter sheets the single copy sequence may be used, either by feeding a number of originals in sequence or by returning a single original from the recovery chute 17 to the feed station 14 for the desired number of times. The sequence of operations performed by the machine in accomplishing these results will .99! bsdsssr best.

OPERATION OF THE MACHINE V The machine, previously loaded with a roll of intermediate and a supply of copysheets, is placed in operating condition by first placing the master switch 22 in the on" position, setting the count switch 25 to the desired number of copies while waiting for the light 23 to indicate the machine to be in readiness, and then merely hand feeding an original into the feed chute 14. Either before or during the copy cycle, the density control switch 26 may be adjusted as desired to control the appearance of the copy obtained. The preliminary delay period permits attainment of full operating temperature at platen 33 and drum 45.

The operation of the machine in making a single copy of a single original will first be described. The original is introduced on chute 14 and is driven by roll 36 against switch 59. Drive rolls 37 and 38 are thereby put into rotation to advance the original over switch 60 and into the nip between drum 30 and intermediate 29. Actuation of the switch 60 results in rotation of drums 30 and 34 to advance the intermediate 29. Simultaneously the light source 31 is lighted and the platen 33 is advanced into contact with the intermediate. A positive pressure is applied within drum 30. The stripper bar 39 remains in position against the drum.

The intermediate and original are exposed to illumination from the light source 31 within the area covered by the reflector 32. As the original reaches contact 63, a sequence is initiated in which the feed roll 51 advances a single copysheet from the tray 50 over the switch 64 and between the feed rolbetween the intermediate and belt 42 in alignment with the section of the intermediate which has just been exposed.

Passage of the trailing edge of the copysheet past the switch 64 initiates a time delay sequence permitting the copysheet to pass beyond the stripper bar 54 and then reversing drums 30 and 34 and returning the intermediate into position for a subsequent exposure. Simultaneously the platen 33 is lifted out of. contact with the intermediate. The drums 28 and 35 maintain the intervening section of the intermediate under constant tension, while the drive unit 34-measures the required lengths for proper positioning of the web.

The original is removed from the drum 30 at the stripper bar 39, the positive pressure within the drum assisting in this operation, and is then advanced by the roll 41 into the recovery chute 17.

As the copysheet passes the stripper bar 54, it is separated from the intermediate and is directed by guide plate 68 back into the nip between the belt 42 and the heating drum 45 where further heat is applied. It is then again separated from the drum and belt at drive'roll 46 and is directed by guide plate 55 into delivery chute 21 and against stop 56.

During the foregoing sequence, passage of the trailing edge of the original beyond the extended lever arm of switch 59 serves to initiate a further sequence by which the lamp 31 is extinguished as the trailing edge passes out of the exposure zone. The short section of the intermediate coming within the exposure area before the lamp is extinguished is thus exposed and lost. The intermediate continues to advance as the copysheet progresses past the stripper bar 54, at which point the direction is reversed and the intermediate returns toward drum 28 until the edge of the unexposed photosensitive portion is in the starting position where it will meet with the leading edge of the original introduced in the next succeeding copy cycle.

Multiple copies of a single original are made by essentially the same operation, modified as will now be described. The stripper bar 39 is initially placed in the open position as illustrated in FIG. 3 to form a continuation of the channel defined by the guide plate 67, and a negative pressure is induced in drum 30. The original is retained against the drum 30 and opens contact 61, thereby preventing initiation of the reversal cycle as the corresponding copysheet passes switch 64. Each successive pass of the original beneath switch 63 initiates a copy sequence in which a copysheet is advanced by roll 51 and rolls 52, 53 into alignment with the exposed section of intermediate so that copies may be made and delivered to the chute 21 in the number indicated on the count switch 25. During the passage of the original for the final copy indicated, the sequence reverts to that described in connection with the single copy mode, resulting in introducing a positive pressure within the roll 30, tilting the stripper bar 39 into the discharge position, and removing the original to the recovery chute, thereby also permitting the reversing mechanism triggered by switch 64 to operate after the final copy has passed the stripper bar 54. In this continuous sequence only about onehalf inch of intermediate is lost between successive exposures.

A further method of operation involves making a single copy of each of a series of intermediates. In this operation a suitable feeding device is supplied at chute 14 for advancing the originals into contact with the roll 36 in close order sequence. Each original is advanced by rolls 37, 38 into exposure position and is subsequently removed to chute 17, again with no more than one-half inch between the trailing edge of the previous original and the leading edge of the next later original. In each case the later original in contact with the switch 66 serves to override the shutdown cycle which would normally be initiated as the previous original passes out of contact with the switch 59, so that the entire series is accommodated. Passage of the final original then deactuates switch 66 and permits the standard shutdown cycle to proceed.

The machine may additionally be programmed to produce a desired plurality of copies, rather than a single copy, of each of a series of originals, thus combining the features of the last two systems just described.

A number of additional features are desirably incorporated in the apparatus of this invention. Depletion of the intermediate 29 is shown on the indicator 24 which is actuated by a switch 65. Another similar switch, not shown, indicates the tearing or breaking of the intermediate when caused by a malfunction of the machine or by other causes. Depletion of the supply of copysheets may be similarly shown. Since originals of undue length or width cannot be effectively copied, a warning circuit may be provided against the introduction of such materials. The jog switch 27 permits an operator to run the mechanism for controlled brief intervals on a start and stop basis for convenience in threading the machine with a new supply of intermediate or for other purposes. The density control switch 26 provides a means for regulating the intensity of the light obtained from the light source 31, for example as required with intermediates of different sensitivity or with originals of different densities. Fan means are incorporated within the apparatus for cooling purposes. The reflector 32 is desirably constructed to permit transmission of heat-inducing infrared rays while reflecting the actinic radiation to the light sensitive intermediate, the infrared then being absorbed externally of the reflector for controlled removal of the energy in the form of heat. Means for adjusting the various circuits and sequences to provide for accurate position, timing, and other functions is desirably incorporated.

A feature which is of particular importance in obtaining a high rate and efficiency of copying is the system of delayed development here employed. The amount of heat supplied by the brief contact with the platen 33 is insufficient to produce any observable darkening at image areas of the copysheet. Surprisingly, subsequent heating of the copysheet, as it passes around the drum 45 develops in the copysheet an image of full density, thus showing the full transfer of reactant is achieved during the preliminary heating step.

In a specific example using commercially available intermediate and copysheets as previously identified, the platen 33 is maintained at a temperature of 250 F. and has a contact area measuring 2 inches along the direction of motion of the intermediate. At a speed of 3% inches per second, and therefore at a contact time slightly greater than one-half second, no visible image is produced on the copysheet. Upon reaching the developer drum 45 the copysheet is heated for a further two seconds at 250 F.; and this additional heating is found to be sufficient to develop the desired intense black image on the copysheet.

I claim:

1. An assembly comprising, in combination, primary heating means for briefly uniformly heating an intermediate while in face-to-face contact with a coreactant copysheet to cause transfer of reactant from image areas of said intermediate to said copysheet without developing on said copysheet a visible image, stripping means for separating said copysheet from said intermediate prior to further heating, and secondary heating means, separate from said primary means, for then further uniformly heating said copysheet to an extent sufficient to develop a visible image.

2. The assembly of claim 1 wherein said stripping means includes a breaker bar.

3. The assembly of claim 1 wherein is included exposure station means for preparing said intermediate by reflex exposure of a composite of a uniformly light-sensitive intermediate sheet material and an original..

4. The assembly of claim 3 wherein said primary heating means comprises a heating platen together with positioning means for placing said platen in either of two positions, namely (l) in heat-conductive pressure contact with said inter- I mediate and copysheet and (2) out of contact therewith.

5. The assembly of claim 3 wherein aid secondary heating means comprises a smooth-surfaced rotatable drum and an endless belt disposed to accompany said intermediate and copysheet past said primary heating means and thereafter to carry said copysheet around at least one-half the periphery of said drum.

6. The assembly of claim 3 wherein said exposure station means comprises a rotatable porous smooth-surfaced exposure drum, guide means for holding an active segment of an elongate strip of said intermediate under tension around approximately one-half the periphery of said drum and over a said original placed thereagainst, lighting means for exposing said intermediate over said one-half periphery, and retaining means for releasably retaining a said original against said drum while free of said intermediate.

7. The assembly of claim 6 wherein said retaining means comprises pressure means for placing the interior of said drum under negative pressure for retaining a said original and under positive pressure for causing release of said original, and including guide means for directing the released original from said drum to a recovery area.

8. The assembly of claim 6 including drive means for advancing a said strip of intermediate to carry a said active segment thereof past said primary heating means and said stripping means. and for then retracting said strip to place a next adjacent segment in position to serve as a said active segment.

9. The method comprising the steps of briefly heating an intermediate, containing a transferrable first reactant at image areas, in face-to-face contact with a coreactant copysheet to cause transfer of reactant from intermediate to copysheet without producing a visible image, and then separating said copysheet from said intermediate and further heating said copysheet to develop a visible image.

10. Method of claim 9 including the step of providing said reactant image areas on a said intermediate by exposing a graphic original to light through a light-desensitizable intermediate sheet material held in reflex position thereagainst, to desensitize the background areas of said intermediate.

i i t i 

1. An assembly comprising, in combination, primary heating means for briefly uniformly heating an intermediate while in face-toface contact with a coreactant copysheet to cause transfer of reactant from image areas of said intermediate to said copysheet without developing on said copysheet a visible image, stripping means for separating said copysheet from said intermediate prior to further heating, and secondary heating means, separate from said primary means, for then further uniformly heating said copysheet to an extent sufficient to develop a visible image.
 2. The assembly of claim 1 wherein said stripping means includes a breaker bar.
 3. The assembly of claim 1 wherein is included exposure station means for preparing said intermediate by reflex exposure of a composite of a uniformly light-sensitive intermediate sheet material and an original.
 4. The assembly of claim 3 wherein said primary heating means comprises a heating platen together with positioning means for placing said platen in either of two positions, namely (1) in heat-conductive pressure contact with said intermediate and copysheet and (2) out of contact therewith.
 5. The assembly of claim 3 wherein aid secondary heating means comprises a smooth surfaced rotatable drum and an endless belt disposed to accompany said intermediate and copysheet past said primary heating means and thereafter to carry said copysheet around at least one-half the periphery of said drum.
 6. The assembly of claim 3 wherein said exposure station means comprises a rotatable porous smooth surfaced exposure drum, guide means for holding an active segment of an elongate strip of said intermediate under tension around approximately one-half the periphery of said drum and over a said original placed thereagainst, lighting means for exposing said intermediate over said one-half periphery, and retaining means for releasably retaining a said original against said drum while free of said intermediate.
 7. The assembly of claim 6 wherein said retaining means comprises pressure means for placing the interior of said drum under negative pressure for retaining a said original and under positive pressure for causing release of said original, and including guide means for directing the released original from said drum to a recovery area.
 8. The assembly of claim 6 including drive means for advancing a said strip of intermediate to carry a said active segment thereof past said primary heating means and said stripping means, and for then retracting said strip to place a next adjacent segment in position to serve as a said active segment.
 9. The method comprising the steps of briefly heating an intermediate, containing a transferrable first reactant at image areas, in face-to-face contact with a coreactant copysheet to cause transfer of reactant from intermediate to copysheet without producing a visible image, and then separating said copysheet from said intermediate and further heating said copysheet to develop a visible image.
 10. Method of claim 9 including the step of providing said reactant image areas on a said intermediate by exposing a graphic original to light through a light-desensitizable intermediate sheet material held in reflex position thereagainst, to desensitize the background areas of said intermediate. 